1. Technical Field
The present invention relates generally to the electronic communication of encoded video data, and more particularly to a system and method of recovering video data between wireless devices.
2. Related Art
As the demand for devices that utilize wireless video applications (e.g., video phones, cellular devices, personal digital assistants, etc.) intensifies, the need to provide systems that can effectively communicate encoded video data has become increasingly important. In wireless and other volatile communication systems where transmission errors regularly occur, data loss is an unavoidable problem. For example, in mobile applications involving cellular devices, a fading condition may occur when the receiver is temporarily located in a position where mountains or other geographic features interfere with signal reception. In other cases, an unforeseen event, such as an airplane passing overhead, may interfere and degrade the signal.
Often, such communication errors are severe enough to cause many bits of data to be lost (referred to as “burst bit errors”). These errors may result in one or more frames of video data being lost. Unfortunately, in typical encoded video applications, such errors may not only cause the receiving device to miss the lost frame, but may also result in the loss of subsequent frames of video data, even if the subsequent frames were received intact.
For instance, in encoding schemes such as MPEG-2 video applications, video frames are encoded using interdependencies among the frames. Accordingly, if a predictive frame (e.g., a P frame) is lost, any subsequent frame that is directly or indirectly dependent on that lost frame cannot be decoded, and therefore would also be lost. Thus, if a P frame is lost during transmission to the receiver, all subsequent P frames received up to the next I frame will not be decodable. Given the fact that P frames typically occur in chains, a high likelihood for losing multiple P frames exists. Depending on the length of the chain of P frames, the amount of lost video frame data could be quite extensive.
Given the high likelihood of errors being introduced into wireless (and other volatile) communication channels, along with the interdependent nature of encoded video frames, a need exists for a system and method that can efficiently recover lost video data.